1. Field of the Invention
The present invention relates to a lens plate, a lens unit, an exposing apparatus, an image forming apparatus, and an image reading apparatus.
2. Description of the Related Art
Existing electrophotographic image forming apparatus incorporate an exposing device for forming an electrostatic latent image on a photoconductive drum. One such exposing device is an LED head which irradiates the charged surface of the photoconductive drum with light emitted from LED arrays using an optical system. Scanners and facsimile machines employ an optical system that forms an image on an image capturing section in which a plurality of light receiving element arrays are arranged.
The optical system includes a plurality of micro lenses aligned substantially in a straight line, the lenses forming an erect image of unity magnification with high resolution. One such optical system is disclosed in Japanese Patent Publication No. 2008-92006. This publication discloses a lens array in which a plurality of lenses are aligned in two adjacent rows such that the distance between the optical axes of adjacent lenses in each of the two adjacent rows is L1. Further, a micro lens in one of the two adjacent rows is between two adjacent micro lenses in the other of the two adjacent rows, and the distance between the optical axes of the two adjacent lenses is L2. The distance L1 is longer than the distance L2.
In order to improve the resolution of an electrostatic latent image, the size of LEDs in the LED head must be reduced to increase the density of dots of light. Decreasing the size of LEDs causes light output of individual LEDS to decrease. Thus, the light emitting efficiency of individual LEDs needs to be improved. In addition, the light generating efficiency of the light source must be improved in order to reduce power consumption.